Woodward 2301E, Инструкция по установке и эксплуатации, Страница: 54 / 182

2301E Digital Control Manual 26641
44 Woodward
Load Pulse / Rejection
The Load Pulse / Load Rejection feature must utilize the PT and CT signals
connected to the 2301E. These signals measure the actual kW Load coming into
the control. The 2301E calculates the derivative (rate of change) of the load, or
basically how fast the load is changing with respect to time. If full load is applied
to a generator, there is a small amount of time where the generator sees the
load, but the engine has not yet started to slow down. We know once the engine
starts slowing down that the PID action of the controller will move the fuel
demand to a position necessary to pick up the load. This feature is used to help
“kick” the speed control and react to the load before the speed starts dropping.
Figure 3.9 shows the effects of the Load Pulse logic.
1.
Graph One shows a typical load transient condition, where a step load is
being applied and removed from the generator.
2. Graph Two shows the typical response of the engine speed as the load step
is applied and removed from the generator.
3. Graph Three shows the Load Pulse being generated from the derivative of
the load step. The graph also shows the load pulse recover rate. This is the
pulse that is added to the speed reference to correct for the large engine
speed variations.
4. Graph Four shows the end results with the Speed Bias Pulse added in. The
result shows a significant improvement.
Figure 3-9. Load Pulse / Rejection